Hydraulic elevator.



C. R. PRATT.

HYDRAULIC ELEVATOR.

APPLICATION men MAR. 10, 1913.

1 156 433. Patented Oct. 12,1915. 7 v 3 inns-SHEET '1.

Fl E.

C. R. PRATT.

HYDRAULIC ELEVATOR.

APPLICATION FILED MAR.'I0, I913.

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VCHABLESFRILPRATT, F MoN'roLAIn, NEW JERSEY, nssieivon 'I'O OTIS. ELEVATOR COMPANY, OF JERSEY GITY,1\TEW JERSEY, A ooEPo A'rIoN OF NEW JERSEY.

HYDRAULIC ELEvAToE,

1 To all whom it may concern:

. Be it known that 1, CHARLES R PRATT, a citizen of the United States, residing in Montclair, in the county. of Essex and State --of New Jersey, have invented a new and useful Improvement in Hydraulic Elevators, of

which the following is a specification. My inventionrelates to elevators or other hoisting apparatus and comprises novel and improved apparatus and means for controlling the same, so as to-provide a simple,

practical and eflicient system of power transv mission wherein power for the hoist is derived from a prime mover or. motor and transmitted-under varying speed conditions to a driven member forming a traction or hoisting element in an elevator system.

The invention is applicable .to the transmission of power in general, and elevators or hoists in particular, and is especially-adapt ed to an elevator operated by thepower delivered by an alternating current motor.

Owing to the general usage of'electricity for power purposes throughout the civiliZ'ed world, and sin'cea large proportion, of this is alternating current, it is but natural that alternating current motors be extensively employed for driving elevators. Since it is a characteristic of such motors to require an enormous current in starting under load, it becomes of great advantage to allow the motor'to operate at substantially constant:

speed in one direction and tointerpose some. form of variable' speed power transmission between the. motor and the load, and to effect the control of the load by controlling the said power transmission. v

In carrying out the invention, I propose to employ a power transmission embodying the difierential gearing between the pilot motor and the traction sheave 0r driven. member; Fig. 4 illustrates, inpart section,

-' a multiple piston variable stroke pump and the method of controlling its stroke; Fig. 5 is a sectional view-of an improved pump.

parts in all of the figures;

Specification of Letters Patent.

Like reference characters denote similar.

Patented oet. 12; 1915.

Application fileanarch 10,1913. se'ria no. 753,180.

Referring to Fig. 1, an alternating current electric motor is designated by the numeral-36, and the same is connected through a main line switch to a suitable source of alternating current supply designated by the 'charactersa, b and The motor 36 oper- V ates at substantially constant speed and always runs in one direction. A small direct current generator 100 is connected to run. with the motor 36 and furnishes a constant potential supply of direct current used in connection with the pilot motor 51, as here-,

inafterdescribed. The power transmission mechanism comprises a pump 37 which is directly connected or coupled to the motor 36 and a fluid pressure engine 38 which may be of any desired type of. fluid pressure motor,'but is preferably of that type illustrated herewith and known as the Brotherhood engine. The same is operated by fluid pressure from the pump 37, through suitable pipe connections such as the pipes 39 and 40, and isconnected to drive a driving element or traction sheave 41; The sheave 41 is connected by any suitable means such as the intermeshing gears 52 and 88, to a difl'erential gear 50. The latter being also connected' through the gears and 86 with a pilot motor 51 equipped with the conventional spring pressed electrically released brake 7 6. An elevator car 42 i suspended from a plurality of cables such .as 43 which are wrapped about thetraction sheave 41 and an idler sheave 44 one or more turns, as desired, and connected at their opposite ends to .a counterbalance weight 45. The differential gear- ,ing 50 is operatively connected by a cable or cables 49 to a sheave 48 associated'with' and operable to control the stroke and output of the pump 37 The wiring diagram shown in Fig. 2 comprises a system of controlling circuits for the pilot motor 51, and the source of current supply designated by the usual characters and is derived from the direct current generator 100 through the circuit controlling switch 104 of Fig. 1. The pilot motor 51' may be of any desired type such as a shunt, series, or compound wound motor, and is here shown as a series wound motor with series field 66. The switch 53 of Fig.

2' is arranged to effect the starting, stopping,

and speed control 'of the pilot motor, and

the same comprises a number of stationary tional speed controlling resistance. Other stationary contacts such. as 64, 63, etc., are connected by conductors to the motor armature, field and brake. A pivoted switch lever'comprising the sections 55 and 70, insulated from each other, is adapted to co-act may be traced from 'the generator 100,

through switch 104 of Fig. 1, conductor seriesfield 66, Wire 65, contact 64, contact 63, wire 62, wire 61, through the pilot motor armature 80, wire 60, sections 58, 57 anl 56 of the resistance, contact 72 and by the main to the generator 100 of Fig.1. 'lhe brake circuit is simultaneously completed: across the and mains at the contact 75. The pilot motor now starts at slow speed." As the switch lever is further moved to the right, the sections 56, 57 and 58 are successively out out. of the motor circuit attended by a further increase in motor speed. If

rupted and the brakeapplied to stop-the motor; while if the switch lever be moved inv a left hand direction the motor armature; con-,1; nectlons will be reversed and the motor will operate in a reverse direction.

r The differential gearing shown indetail',

fixed to it a spur gear 88 and bevel gear .78,

A bevel gear 87 similar. to the gear 78 is: loosely mounted on the shaft 77, and is'rigidly connected by a key 84 or other suitable mechanical fastening to the spur "gear 86 similarly mounted onthe shaft 77. A plu- 'f p s g box2, roller. thrust bearfling 3, and "journal bearing4I On the'shaft 1 rality of bevel gears 90, 90, arecarried upon the inner circumference of the sheave 50 and are adapted to rotate and mesh with the adjacent gear teeth of the. bevel gears 87 and f 78. If the bevel gear 87 be operated by the pilot motor at the same speed-as the bevel gear 78 is driven from the traction sheave;

but in a reverse direction, it will be seen that the sheave 50 will remain stationary while' the small bevel gears 90, 90, will freely rof,

tate, each upon its ownpivota If the speed of the gear 87 varies from that of the gear 78 the sheave 50 will be' rotated iii the direction of the faster gear andfat a speed equivalent to thediflerential lspeed ofthe two gears 'Now, since the gear/Z8 is driven v by the traction sheave or'driven member 41,

while the gear 87 is driven by the pilot motor 51 at any desired speed and'direction of or piston .6 is aconnecting rodsl2 with a ball rotation, the sheave 50 will effect the control and output of the pump 37 so as automatically to synchronize the speed of the pilot motor. and traction sheave or driven element 41 through the cables 49 connecting thedif-i ferential gear with the control sheave 48, of

the pump- (see Fig. 1). Turning now to. Fig.4, I will describe the operating connection between the diflerential gear mechanism and the pump, showing the manner inwhich the pump stroke and resultant pump output is controlled and regulated. The pump shown in vEig. .4 is intended to be a diagrammatical representation of the pump shown in Fig. 5, and showing the pump strokecontrolling mechanism. The axis of the latteris shown inclined with I respectto the axis of rotation of the pump, and I propose to vary this angle whenever desirable so as best to accommodate the lead of the cables 49 connected thereto for different elevator installations: The pump 37 comprises a tilting-head 9 whose axis may coincide with the axis of the pump shaft 1 corresponding to aneut'ral position or .posi- 90 tion of zero output of the pump, or whose axis may be inclined to the extent of its.

tiltinghead is provided with teeth 101 meshthe switch lever be centered 01- brought back to off position, the motor circuit is'intei-gtion being suchythat a rotary jmovement of the sheave effects a movement of thetilting head and a resultant variation in. pump stroke-' 1 I d0 not deem it necessary 'to'illus I "1 itrate or describe the suction andpressure' Q: chambers of the pump, and the arrangement in Flg. 3 comprises a shaft 77 mounted to! rotate in bearings 83, 83, and having=-af ofvalve ports, since the same is'well known the art, and an 'example of which is found I 111;" Patent .flfrri'm the prime-'m'over 36, enterstheport 1 chamber 'or right-hand 'end -of the v pump ispressed and keyed byja' key 95,;a cylinder p lu'ngersor pistons'6, having their axis par.

ing 7 in th'epump casing 8. "Pivoted trunnions'97. in the casing 8"is the tilting head 9'which carries a roller thrust bearing.- 10 for the rotary disk 11. In each plunger.

and socket bearing atone end in the plun er 6jand a similar ball and'socket at the ot er end in the disk 11. Ajsp'herical collar 13 "shbwn on the shaft 1, rotatable th'ereonand movable longitudinally ther of, i -13f al'lel' to each. other and'to the-shaft 1,. and symmetrically disposed about'the said shaft. PThe inner or left hand end ofthe latterfiis; "supported in andfcarried by a'journ'al bear- 2 to take theradialthrust bf disk 11, and, a

the shaft 1, collar 13 and disk 11, all revolveoperation of the pump as will be shown hence all of the rods 12 transmit the tor.

later, but its presence "is desirable, as it adds to the strength of the pump and has other features of practical value. The plungers 6 are of su'chlength,- and are guided at each end by bushings 1i and 15, between which is packing 16, sothat they 'are able to transmit the torsional strain of shaft 1 by means of the connecting-rods 12 to the rotating disk '11. Bushings 17 inthe end ofeach' plunger 6 allow for the slight circular motion of the connecting rods 12, during each revolution,

sional load-at the same time with no end motion at-theirend contacts and they also carrythe radial load er the disk 11. Ill order to automatically take up the slight wear occasioned by long, continued use of the pump'and to avoid lost motion at the ball and socket hearings in the rods 12,

their suction stroke spherical collars 18 and 93 are held against the balls by springs,

such as.1 9,'in the'plungers and by several springs '94 in eachball sooket in. disk 11. Cylinder barrel 5 is causedto run true with respect to'its valve seat' 20 by the rigidity of the shaft l'to which it is attached by key 95 and collar 96, and is held at a film thickness 'of'fluid distance from its seat by adjusting nut 21 and rollerthrust bearing 3. In order to obtain a fine adjustment of the adjusting nutt21, a differential lock nut washer- /23 keyed to shaft 1 by a feather 24and locking teen pin holes in the part 23 and-twenty pin holes in. the part 21, and assuming the threaded portion of the shaft has twelve 7 threads to the inch, gives an adjustment of 1/4560 parts of an inch to the nut 21.; .For

safe and convenient locking of pin '25,"a--' spring ring 26 in a groove in nut 21, snaps "into" a slot in'pin'25, a half turnof pin 25 unlocks it for removal, and pushing it'in' with its beveledend toward th'e spring, lifts the spring and allows it to snap back into the locking slot'in pin 25. j

" Lubricationof all bearing surfaces is obsaid power transmission mechanism. hole 103 in the center of shaft 1, feeding oil I first *to the journal bearing 7 then through tained by centrifugal circulation through a radial holes 27 in shaft 1, and collar 13130 "ducts-in disk 11, feeding the 'rollerthrust bearing 10, whereit is retained by centrifuand' through holes lengthwise, of the connecting'rods 12 to the ball and socket bearings in the several plungers. The oil or lubricant also flows through the center duct 103 in the shaft 1, through radial holes 28,

to the plunger bushings, and also through radial holes 29 to'the end thrust and journal bearings at the right hand end of the pump. Vvhen the spherical collar 13 is not used the oil from the radial holes 27 is thrown by centrifugal force into the inner groove 1n.

disk 11, and flows, as before pointed outto the roller thrust-bearing 10, and ball and socket bearings of the connecting rods and associated 'parts. The interior of casings 8 and 30 can be kept free of lubricant and also free of the fluid being handled by the pump by. means of separate drip pipes for each. Also toinsure ample lubrication, a small oil pump and reservoir can be easily arranged to, maintain a substantial" stream of oil flooding all-bearings and other parts subject to'wear. 'For the complete separation of the lubricant from the fluid being pumped, holes orv ducts. 31 discharge all'ithe oil from the of wall 35 and out of hole 32, in casing 8,

plunger lubrica'tors to one side with the balanceofthe lubricant; and all leakage of the fluid pumped"leaki11g out of valve seat 20 and through the plunger packing by hole 33,'is held'on the'other side;

of wall 35 and discharged out of hole 34 in a casing 30,- either to waste or suction. i

WhileI have illustrated and described a preferred construction, and embodiment of to the pump my invention, I desire not to .be limited-to the precise construction and, arrangementof parts herein set forth, since it is obvious that one skilled inthe art could readily make various changes in the apparatus disclosed without departingfrom the spirit and scope of the invention.

What I claim as new and desire to secure nut 21 by pin 25, with, for eXample, nine-- by Letters Patent of the iUnlted States 1s:-.

1. .In an elevato'rythe combination with a a constantly rotating shaft, a; hoisting drum or sheave, fluid'power transmission mecha' 'nism operatively connecting said shaft and sheave, and electrically controlled. difl'erential mechanism for controlling-said power.

, transmission mechanism.

In an elev ator the combination 'witha constantly rotating shaft,i-a]hoisting drum J 001- sheave, fluid power transmission mechanism; operativel'y 'connect-ing 'sai d shaft and sheave, and difierential mechanism connected togsaiddrum or sheave for controlllng C5 .f to the'ball and socket bearings with said drum or sheave, differential mechanism' operatively connected to said drum anism operatively connected to said drum or sheave and to a motor, and means for controlling said motor to effect the control of the said power transmission mechanism.

4. In an elevator, the combination with a constantly rotating shaft, .a hoisting drum i or sheave, fluid power transmission mecha- 'nism arranged totransmit power from said shaft to a 'load carrying deviceassociated with said drum or sheave, differential mechor sheave and to an electric, motor, and means for'controlling said motor toe'fl'ect the controlof the said. power transmission mechanism. 1

I 5. In an elevator, the combination with a constantly rotating shaft, a hoisting drum or sheave, fluid power transmission mechanism arranged to transmit power from said shaft to a load carrying device associated vwith said-drum or sheave, diflerentialmech- I anism operatively connected to said drum or sheave and to a motorfand means located on said load carrying device for controlling said motor to effect the control of the said power. transmission mechanism.

-' 6. In an elevator, the combination with a 7 constantly rotating shaft, a hoisting drum or sheave supporting an elevator car, fluid power transmission mechanism operatively connectinglsaid shaft and drum or sheave, a

variable speed electric pilot motor controlled from said car, and means for controlli the said gpowert'ransmission mechanism by the differential" action of said pilot motor and power transmission -mechanism.

. 7. In an el'evator,the combination with a constantly rotating shaft, a hoisting drum or sheave supportmg an elevator car, fluid power transmission mechanism operatively connecting said shaft and drum or sheave,

1a variable speed electric pilot motor con-v trolled from said car, and differential mech ani'sm connected to run with said pilot motor and hoisting drum or sheave,'and' arranged to control the power transmission mech'aa nism and thereby-cause the ,said, hoisting drum 'or sheave toi run n synchronism with rthe saidpilot motor. 1 5. v

* alternating current, motor adaptedto run at 8. anelevaton the combination with an -"substantially constant speed in one. direction, a" hoisting drum or sheave, fluid power transmission (mechanism connecting said --moto'rj.and sheave, a' pilot motor for. controlling said"'power transmission mecha-v nism,"a generator drivcn-bylsaid. alternatingi clj'l'rren't motor and adapted to-supply -eleci tric current to-s aid pilot-motor, and means for controlling, the current to said. pilot "9. an elevator, combination with a name to this specification in the constantly running power motor, a hoisting drum or sheave, a fluid pressure engine 0peratively connected to said sheave, a pump driven by said motor and connected to said fluid pressure engine,.means for controlling the output of said pump to vary the speed and power of said engine, and a rotary electric pilot motor adapted to control the operation of said pump controlling means.

v10. In an elevator, the combination with a constantly running power motor, a hoisting drum or sheave, a fluid pressure engine operatively connected to said sheave, a pump driven by said motor and connected to said fluid pressure engine, and a pilot motor adapted to control the operation of said pump controlling means according to the differential. speed of the said pilot motor and sheave or drum.

11. In a fluid pressure power transmission a hydraulic power unit, an electric pilot motor, and means for-synchronizing the said unit with the said motor.

- 12. In a fluid pressure power transmission, a hydraulic power unit operatively co'nnectedto 'a gravity load, a pilot motor, and means for synchronizing the said unit and pilot motor.

13. In a fluid pressurepower transmission, a hydraulic power unit operatively connected. to a gravity load, a pilot motor, and means for synchronizing the said unit and pilot motor actuated by both the pilot motor and by the said hydraulic power unit.

14. In a fluid pressure power transmission, a hydraulic power unit operatively connectferential gearing for synchronizing thesaid unit and pilot motor.

15. J In a fluid pressure power transmission, a hydraulic power unit operatively connected to a gravity load, a pilot motor, differential gearing for synchronizing the said the lubricant separated from the fluid acted upon by the said-plungers.

In testimony whereof, I have signed my of two subscribing witnesses.

' CHARLES R. PRATT.

Witnesses: v

' WALTER C. STRANG,

J. G. BETHELL.

presence ed toa gravity load, a pilot motor, and dif- 

